#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
using namespace std;

const int N = 1e6 + 10, INF = 0x3f3f3f3f;

int n;
vector<int> a, b;

void solve()
{
    cin >> n;
    for (int i = 1;i <= n * 2;i++) {
        int x;cin >> x;
        if (find(a.begin(), a.end(), x) == a.end()) a.push_back(x);
        else b.push_back(x);
    }
    for (auto it : a) cout << it << ' ';
    cout << '\n';
    for (auto it : b) cout << it << ' ';
}

signed main()
{
    // ios::sync_with_stdio(0);
    // cin.tie(0);cout.tie(0);
#define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
    std::istringstream in(R"()");
    std::cin.rdbuf(in.rdbuf());
#endif
    int T = 1;
    //cin>>T;
    for (int i = 1;i <= T;i++) {
        solve();
    }
}